On the fit of statistical and the k-C* models to projecting treatment performance in a constructed wetland system

Abstract

The objective of this study was to assess the suitability of statistical and the k-C* models to projecting treatment performance of constructed wetlands by applying the models to predict the final effluent concentrations of a pilot field-scale constructed wetlands system (CWs) treating animal farm wastewater. The CWs achieved removal rates (in g/m².d) ranging from 7.1–149.8 for BOD₅, 49.8–253.8 for COD and 7.1–47.0 for NH₄-N. Generally, it was found that the statistical models developed from multiple regression analyses (MRA) were stronger in predicting final effluent concentrations than the k-C* model. However, both models were inadequate in predicting the final effluent concentrations of NO₃-N. The first-order area-based removal rate constants (k, m/yr) determined from the experimental data were 200.5 for BOD₅, 80.1 for TP and 173.8 for NH₄-N and these indicate a high rate of pollutant removal within the CWs.

Keywords:

• Alum sludge
• constructed wetlands
• first-order
• k-C* model
• regression analysis

Acknowledgments

Authors gratefully acknowledge financial support received for this field study from: (1) Enterprise Ireland under the Proof of Concept Scheme (project No. PC/2007/0308); (2) the Irish state Department of Agriculture, Fisheries and Food under the Research Stimulus Fund (project No. RSF 07-528). The UCD farms, Lyons Estate, Newcastle, Co. Dublin, Dr Edward Jordan and Mr Michael Hegarthy are all sincerely thanked for their support for the field work.